1. Field
The present invention relates to an axial flow fan, and more particularly to an axial flow fan capable of distributing rotational stress, by overcoming a problem of the concentration of stress caused during rotation thereof.
2. Description of the Related Art
A fan is a mechanical device used for ventilation or cooling of heat by generating an air current, generally including a centrifugal fan and an axial flow fan. Whereas the centrifugal fan achieves a relatively low volume flow and a high constant pressure, the axial flow fan achieves a relatively high volume flow and a low constant pressure. Accordingly, the axial flow fan is used mainly for cooling.
The axial flow fan is structured to comprise a hub having a substantially cylindrical form, and a plurality of wings extended from the hub in radial directions.
The performance and the noise property of the axial flow fan are determined by a 3-dimensional shape of the wings. Recently, the performance and the noise property of the axial flow fan have been greatly advanced by optimizing the 3D shape of the wings.
Additionally, a safety factor of the axial flow fan may be determined by the mechanical property thereof. More specifically, in a case where the axial flow fan rotates at a high speed or the axial flow fan has been used for a very long time, cracks may generate due to stress concentrated on one certain part. The safety factor is subject to such mechanical property. For example, since a connection part between the hub and the wing has an abruptly changing shape, stress would be concentrated on the connection part, thereby highly increasing the incidence of the cracks. In order to reinforce strength of parts where the cracks are likely to occur, a dedicated member has been attached to the parts.